Week 4 lecture: flower parts and pollinators Flashcards
Early gymnosperm sperms
flagellated (ginkos and cycads)
difference: don’t have to wim through WATER they swim through pollen tubes
Pollen tube
for sperm transfer (gymnosperms and on)
point at which we’ve broken free of needing standing water/films of water.
Major difference between gymnosperms and angiosperms- what makes gymnosperms unique?
cones for reproduction in gymnosperms (naked ovules); early versions still have flagellated sperm.
conifers similar to angiosperms in some ways. no flagellated sperm. Lack most other repro structures of flowering plants.
Confiers DO NOT have double fertilization; do not have a secondary covering for their seeds “naked seeds”
angiosperms: double fertilization. Have another seed covering
What are gnetophytes?
like ephedra, wellwitchia. Important gymnosperms.
Have double fertilization (twin seeds)
Just about as old as angiosperms
What did darwin call the abominable mystery?
the rapid development of higher plants (angiosperms)
They underwent massive adaptive radiation, appear to have been around 140 mya.
There’s a gap during the jurassic period and then all the sudden there’s gnetales and flowering plants.
Name the two specialized structures of the flowering plants.
pistil and anthers (mega and microgametophytes)
Pistil, ovules, and vessel seeds are unique to..
angiosperms
how do we think gametophytes evolved?
leaf modification
microsporangium evolved to leave the spores (pollen) on the outside of a tightly wound leaf.
megasporangium evolved to wrap the ova inside, fuse along a suture and become a “conduplicate carpal” Seam holds ovules
Can you tell angiosperm and gymnosperm pollen apart?
Yes. gymnosperms look like balloons for travel. Angiosperm are highly modified and convoluted.
There can be tracheids and vessel elements for gymnosperms, angiosperms, and gnetales. What’s the normal distribution?
Gymnosperms= tracheids.
gnetales; most angiosperms= tracheids and vessel elements
early angiosperms only have tracheids.
additional pipe of vascular elements
Describe a gymnosperm leaf; contrast it with an angiosperm leaf.
gymnosperms have dichotomous venation= every vein splits to 2, not parallel like monocots.
angiosperms= parallel veins (monocots) OR net veins (cross a lot, dicots)
note: highly modified needle-like leaves
exception: gnetum, has netty leaves; morphologicaly it’s very similar to angiosperms.
morphological data and molecular data suggest what about the relationship between gymnosperms and angiosperms?
that we know nothing.
cycads: pretty different. potentially closest relative (molecularly)
morphologically: gnetum, ephedra, and welwitschia are most similar (ALL HAVE NECTARIES)
angiosperms are far more diverse than..
gymnosperms (re less than an order of magnitude than angiosperms
only more successful group is insects. most successful on the planet.
fragmentation and isolation probably led to this diversity.
How did plants drive animal/insect diversification?
mutualisms
rise of flowering plants is associated with the diversification of lots of other species.
What species REALLY increased its diversity with the appearance of angiosperms?
butterflies.
Bees and wasps were already diversifying
Earlist angiosperm reproductive structure; what did flowers look like?
bracts, bracteoles
Wasn’t trying to attract animals, trying to protect its reproductive bits.
early on arms race
